diff --git a/onionshare/__init__.py b/onionshare/__init__.py
index a3474da9..78f754fc 100644
--- a/onionshare/__init__.py
+++ b/onionshare/__init__.py
@@ -68,7 +68,7 @@ def main(cwd=None):
     # Validation
     valid = True
     for filename in filenames:
-        if not os.path.exists(filename):
+        if not os.path.isfile(filename) and not os.path.isdir(filename):
             print(strings._("not_a_file").format(filename))
             valid = False
         if not os.access(filename, os.R_OK):
@@ -102,8 +102,12 @@ def main(cwd=None):
 
     # Prepare files to share
     print(strings._("preparing_files"))
-    web.set_file_info(filenames)
-    app.cleanup_filenames.append(web.zip_filename)
+    try:
+        web.set_file_info(filenames)
+        app.cleanup_filenames.append(web.zip_filename)
+    except OSError as e:
+        print(e.strerror)
+        sys.exit(1)
 
     # Warn about sending large files over Tor
     if web.zip_filesize >= 157286400:  # 150mb
diff --git a/onionshare_gui/__init__.py b/onionshare_gui/__init__.py
index 83d03cc0..14c76617 100644
--- a/onionshare_gui/__init__.py
+++ b/onionshare_gui/__init__.py
@@ -91,7 +91,7 @@ def main():
     if filenames:
         valid = True
         for filename in filenames:
-            if not os.path.exists(filename):
+            if not os.path.isfile(filename) and not os.path.isdir(filename):
                 Alert(strings._("not_a_file", True).format(filename))
                 valid = False
             if not os.access(filename, os.R_OK):
diff --git a/share/locale/en.json b/share/locale/en.json
index 30e0c196..05873e26 100644
--- a/share/locale/en.json
+++ b/share/locale/en.json
@@ -8,7 +8,7 @@
     "give_this_url": "Give this URL to the person you're sending the file to:",
     "give_this_url_stealth": "Give this URL and HidServAuth line to the person you're sending the file to:",
     "ctrlc_to_stop":  "Press Ctrl-C to stop server",
-    "not_a_file": "{0:s} is not a file.",
+    "not_a_file": "{0:s} is not a valid file.",
     "not_a_readable_file": "{0:s} is not a readable file.",
     "no_available_port": "Could not start the Onion service as there was no available port.",
     "download_page_loaded": "Download page loaded",